Eclipse 3.x plugin of Library Folder ClasspathContainer http://www.eclipse-plugins.info/eclipse/plugin_details.jsp?id=409). This plugin will add all .jar and .zip files of a folder to you classpath. To install, visit http://libcontainer.sourceforge.net/
Excellent Eclipse plugin that seems to work from Indigo thru to Kepler. Our large commercial Java project has many dependent jar files that each developer had to manually update/delete their project classpath. We were suffering from class 'jar' hell. This plugin simplifies the whole process for us. Terrific!